1. Field of the Invention
The present invention relates to an improved system for the treatment of stress urinary incontinence, which provides essential characteristics of novelty and appreciable advantages in relation to the known methods and devices used for the same purposes in the related art.
2. Description of the Related Art
The fact that stress urinary incontinence is a frequent pathology in women is generally known, involving urine loss when abdominal stress is performed such as coughing, going from the sitting position to that of standing up or walking.
This problem is an illness which frequently causes a serious reduction in the quality of life, as a consequence of the voluntary limitation of multiple activities, due to fear and shame that this urine loss may be noted by other people, and which often leads to situations of loneliness and isolation.
The anatomic alteration that lies behind this urine loss symptomology induces the descent of the vesical neck and the urethra due to the alteration of the perineal muscles, and which can be caused, among other reasons, by giving birth. The descent of the vesical neck and urethra means that abdominal pressures are not correctly transmitted thereto, this set of altered pressures being the cause of the involuntary urine leaks.
Until now, some techniques have been proposed that tend to provide solutions to this problem. In any case, the solution to the problem of incontinence is surgical and involves returning the vesical neck and urethra to their original position, then providing them with a support that permits the correct transmission of abdominal pressures thereto. Amongst the techniques used, that known as the sling technique is the one which provides a more efficient, lasting solution.
This sling technique involves placing a tissue band, whether from the patient herself or heterologous tissue (marlex, silicone and, lately and with improved results, prolene), in a sub-cervical or sub-urethral position, so that once the band is fixed in different points according to the technique, it lifts and supports the vesical neck and the urethra in their original position, thus enabling pressure transmission and avoiding urine loss.
The tissue band can be sufficiently long to go from the urethra to the hypogastrium, or it can include only a small patch joined to several (e.g., four) threads, that are later attached to the abdominal wall.
The aggressiveness of the technique has been considerably reduced since it is performed intravaginally, without needing to open the pelvic cavity, and since prolene has been used, as it avoids having to collect aponeurosis from the same patient.
Recently, within the concept of this surgery as non-evasive, two sets have come onto the market for urinary incontinence surgery, identified by the acronyms TVT and SPARC. Both use a polypropylene mesh, surrounded by a plastic cover, and a connector system using a needle with a handle. Both techniques are differentiated in that, in the case of TVT, the needle is passed through the vagina towards the hypogastrium, needing to separate the urethra with a probe and a catch, whilst in the case of the SPARC technique, this step is performed in the direction of hypogastrium to the vagina, without the urethra needing to be separated by a probe. In both cases, the polypropylene mesh used, surrounded by a plastic cover, is passed through the vagina to the hypogastrium, which has facilitated the mesh passing through, leaving the latter positioned subcutaneously, where it is fixed due to the properties it has been provided with.
In both techniques, and all those wherein the sling system is used, an important problem is correctly adjusting the tension given to the sling, a special feature that conditions the success or failure of this type of surgery. Furthermore, if this sling is subjected to excessive tension, a urinary obstruction may occur, so that the patient will have difficulties in eliminating urine. In contrast, if sufficient tension is not provided, the patient will then continue to have an incontinence problem.
There is, therefore, a practical difficulty associated with the fact that there is no way of calculating the most appropriate tension, having to do so randomly and approximately. Once the operation has concluded, it is then not possible to correct the excess or lack of tension, which leads to a failure rate estimated at between 10% and 20% of the operations. Furthermore, this problem is the cause of all failures which occur with the application of this technique.
The existence of a system identified as REEMEX is also known in the market, wherein a subcutaneous implant of a device in the form of a pulley is performed in the hypogastrium, which permits, with the use of a screwdriver, and during the postoperative, to increase the tension given to a sling formed by a small patch of tissue fastened with four threads. This system is expensive, complex and suffers from considerable potential complications, due to the fact that it requires the implantation of a foreign body. It also can be loosened if the sling has been made with threads, but the system cannot be used when it uses a sling only formed from mesh, i.e. of TVT or SPARC type.
Finally, there is another system currently in existence, although there is no knowledge of its commercialization, consisting of a development by Dr. Gil Vernet, which includes a liquid reservoir implanted in subcutaneous tissue in the hypogastrium. The threads which fasten the sling have been attached to the reservoir. The system allows, if there is little tension, that the reservoir can be filled with liquid, thereby increasing the tension. The system is of equally difficult clinical application, and cannot be used with complete meshes.
Another technique that has recently appeared is TOT, which differs from the previous techniques in that the mesh is passed through the obturator foramen instead of the hypogastrium, with the same intention of returning the urethra and the bladder neck to their correct position. This technique presents the same difficulty of adjusting the exact tension of the mesh, which also results in a significant failure rate.
In accordance with the previous description, the systems used in the application of the sling technique have a series of drawbacks associated with their use, which do not permit the fully satisfactory use thereof.